Human Systems Integration Division @ NASA Ames

The X-15 program operated three hypersonic, high-altitude rocket-propelled single-pilot aircraft from 1959 until 1968. The third aircraft, X-15-3, was involved in a fatal accident on November
15, 1967. X-15-3 was the most advanced aircraft flown during the program and carried a variety of sophisticated instrumentation and electronics, including the MH-96 adaptive flight control
system (AFCS).

The X-15-3 aircraft was destroyed during atmospheric entry after entering uncontrolled flight at an altitude of 230,000 feet and a velocity near Mach 5. The pilot, United States Air Force (USAF) Major Michael J. Adams, was incapacitated by the aircraft accelerations and was killed either during the ensuing breakup or upon ground impact.

To better understand the risks to emerging aerospace systems incorporating advanced technologies such as adaptive flight control, the NASA Engineering and Safety Center (NESC) organized a comprehensive assessment of this fatal accident in light of almost 50 years of accumulated experience in flight operations, human factors, and flight control. The report of the 1968 NASA/United States Air Force Accident Investigation Board (AIB) was used as a point of departure for the present assessment. The goal of the study was to characterize the causes of the loss of life, as well as to determine, at a level of detail not addressed in the original report, the exact role of the MH-96 AFCS in the accident.